Carl Safina headed down to the Gulf Coast just days after the Deepwater Horizon rig exploded on April 20, 2010. A veteran of the Exxon Valdez spill — and the head of the Blue Ocean Institute, a nonprofit that focuses on marine health — Safina wanted to see the Gulf oil spill up close, to document something he was sure would be an environmental catastrophe. Researching what would become the book A Sea in Flames — which goes on sale April 19 — Safina spent time with Gulf fishermen and ecologists, toured oiled beaches and spoke to people involved in the cleanup. As long as the oil kept spilling, just about everyone had the same opinion: the spill would be truly catastrophic for the Gulf and its coast. “We didn’t know how it would stop or when it would stop,” says Safina. “Gulf fishermen who’d invested their lives in the industry were convinced they’d never fish again.”

Yet nearly a year after the spill began, it seems clear that the worst-case scenario never came true. It’s not that the oil spill had no lasting effects — far from it — but the ecological doomsday many predicted clearly hasn’t taken place. There is recovery where once there was only fear. “A lot of questions remain, but where we are now is ahead of where people thought we’d be,” Safina says. “Most people expected it would be much worse.”

As we approach the anniversary of the spill, Safina’s judgment is becoming the accepted wisdom: it could have been worse. That isn’t to minimize what did happen in the Gulf of Mexico. Roughly 4.9 million barrels of oil blew out of BP’s broken well and bled into the water, with a portion of that crude making landfall along the coastline. Add in the unknown effect of 1.84 million gallons (7 million L) of chemical dispersants, much of which were applied directly to the well deep below the surface of the ocean — something that had never been done before. Even the cleanup might have had an impact on the environment, thanks to the burning of oil on the surface of the Gulf, and the tens of thousands of workers who trampled along the sensitive wetlands of Louisiana, corralling crude wherever they could. Scientists caution that a single year isn’t long enough to draw any final conclusions about an environmental insult so huge.

Yet the damage does seem so far to have been less than feared. Take the oil itself: scientists with the National Oceanic and Atmospheric Administration estimated last August that much of the oil had remained in the Gulf, where it had dispersed or dissolved. Many environmentalists attacked the report for underplaying the threat of large underwater oil plumes still active in the Gulf, yet later independent scientific studies indeed found that oil had largely disappeared from the water. Turns out we can thank bacteria. Scientists from Lawrence Berkeley National Laboratory; University of California, Santa Barbara; and Texas A&M University traveled to the site of the blown well and found that microbes had digested much of the oil and methane that remained in the water. By autumn, the levels were back to normal. “It’s very surprising it happened so fast,” John Kessler, an oceanographer with Texas A&M, told me earlier this year. “It looks like natural systems can handle an event like this somewhat on their own.”